Two-stroke-cycle internal-combustion engine.



J. R. KEMP. TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED JAN. 26. I914. 1,242,450. Patented Oct. 9,1917.

2 $HEETSSHEET l- M Q Q 1. R. KEMP. TWO-STROKE CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED 1AM- 26. I9I4.

1,242,450.} Pate nted 0011.9,1917.

2 SHEETS-SHEET Z.

s m M J'AJIES' REGINALD KEMP, or NEWEUEY, ENGLAND.

TwO-STROKE-CYCLE TlINTERNAL-COMBUSTION ENGINE.

To all whom it may concern Be it known that I, JAMES REGINALD KEMP, a subject of the King of GreatBrithay, N ewbury, Berkshire, England, have'inain, and a resident of Oakhurst, Woodvented new and useful Improvements in Two-Stroke-Cyde Internal-Combustionldm gines, of which the following is the specification.

This invention relates to improvements in.

two stroke cycle internal combustion engines.

The objects of this invention are (1) to provide a two stroke engine in which there shall be a practically perfect balance of the moving parts, (2) to provide a two stroke engine in which the combustion or working stroke takes place between two pistons connected to opposed cranks without any neces sity for employing outside connecting rods, and (3) to provide a two stroke engine in which the pump faces of the two working pistons serve, the one as a mixture pump,

and the other as a scavenging pump, thusobviating the necessity for the employment of an additional pump or valve. I

My invention relates to that kind of en gine in which in a single cylinder two an-- nular pistons are fitted each formed with a tubular or trunk extension, the one adapted to slide within theother, and in which there are-three crank pins on the crank shaft, one

inner and two outer, the latter being placed at 180 degrees from the former. According to my invention, one end of each of the annular pistons serves a's-a pump to su ply a central combustion chamber between t e pistons, and a central channel open to the air at the upper end is formed through both piston trunks. a

The inner sleeve trunk piston is connected by its connecting rod to the central crank pin. The flange forming the upper annular piston is preferably integrally formed at the extreme outer end of the sleeve or tube and may conveniently be formed hollow, or

of double annular walls. The outer edge of the flange slides upon the cylinder wall and is of'suflicient depth to carry suitable packing rings. r

The second annular pistonis at the extreme outer or upper end of its tube or trunk,

and'theouter surface is also provided with Specification of Letters Patent.

. L Application-filed January 26,1914. Serial No. 814,552.

Patented Oct. 9, 191 '7.

packing contacting with the cylin- There is also preferably formed with the said head, 2. depending suitable der wall. integrally extension sleeve adapted to reciprocate in contact with the cylinder wall. The cylinder cover is provided with an in ner downwardly depending stationary tube or sleeve fitting within the inner trunk piston. The interior of the stationary sleeve is open to the outer air.

The outer of the two sleeves, that carrying the lower annular piston is provided on its exterior at its lower end with preferably,

two pins or studs forming gudgeon pins, to

which are connected two connecting rods fitting at their lower ends the two outer crank pins. The exterior surface of the outer tube or piston trunk slides within a-stationary sleeve or tube secured to the crank chamber, and closing the lower end of the cylinder. By this arrangement all connecting rods are within the crank chamber.

A ring of exhaust ports is formed in the outer cylinder walladapted to be uncovered by the lower annular piston just prior to, and at .the lower dead point of its stroke.

Shortly after the said exhaust ports are uncovered, the upper annular piston uncovers passages formed longitudinally in the cylinder wall whereby the scavenging air is transferred from the pump side of the upper annular piston where it has been previously compressed, to the working side thereof. As the scavenging air is thus delivered at the opposite end of the annular combustion chamber to that at which the exhaust gases leave the cylinder, the scavenging is more efficient. Shortly after the delivery of scavenging air and preferably before the scavenging air ports are closed, the mixture is delivered by the pump at the other end of the cylinder, the mixture having been previously compressed by the lower face of the lower annular nels is or are provided to convey the mixture from the lo *er end of the'cylinder to the upper endfor delivery. The said channels piston. A channel or chanmay be formed integrally with the cylinder wall.

Alternatively the upper piston may draw in mixture and the lower piston may draw in scavenging air.

Combustion therefore takes place between An ignition plug is fitted approximately,

midway in the cylinder.

The sleeve connected to or formed integrally with the lower piston sliding upon the cylinder wall, serves not only to close the exhaust ports when the portsleading to the carbureter or the like, are open for the in.- duction of mixture to the lower pump, but it also serves to close the mixture inlet ports when compression of the mixture occurs for delivery to the working cylinder.

'hen the described construction is employed with a Diesel or semi-Diesel cycle both annular pumps may be employed for the delivery of air to the working cylinder;

And in order that my invention may he completely understood reference should be made to the accompanying sheets of drawings which illustrate one example of my invention diagrammatically.

Figure l is a vertical sectional elevation of a twin cylinder engine in the plane of the crank shaft, the right hand piston bein shown in part section and in the position 0 maximum compression.

Fig. 2 is asection of the left hand cylinder shown in Fig. 1, but at a right angle therewith.

Fig. 3 is a plan section of the left hand cylinder of Fig. 1 on the line Y Y.

Fig. 4 is a plan section of Fig. 2, on the line X X.

-Fig. 5 is a plan of the upper annular piston.

Like reference letters refer to like parts in each of the figures and the two cylinders shown in Fig. 1 having similar working parts in each cylinder have like reference letters.

A is the cylinder within which the two opposed pistons B and C reciprocate. The

- upper piston B of annular form is either rigidly secured to the tubular trunk B or is integrally formed with it: The lower end of the trunk B is formed with a bridge piece B secured to which, by the nuts shown, is the detachable cross-head B which crosshead carries the gudgeon pin B by which the connecting rod B is connected to the crank pin D of the crank shaft D. The channels R and B on each side of the bridge piece B allow free passage of air to the crank chamber.

The cylinder cover A has formed inte-' grally with it, the tubular extension or sleeve A which fits telescopically within the piston B and its trunk B. The cylinder A has formed on its inner surface the longitudinal passages E, which passages efiect the transfer of the air, supplied as afterward described compressed or displaced by the upper face. of the annular piston B from the naaaaeo annular spaceahove the annular piston B to the. lower side orworkingface of the said is similarly provided with the trunk or tubus lar extension C, which projects within the crank chamber F, and is provided at its lower end with the two lateral pins C C forming the gudgeon. Connected to the pins C C are the connecting rods C C respectively. The big ends of these connecting rods fit the crank pins D D of thecrank shaft 11).

The surface of the lower annular piston C reciprocates therefore upon the trunk 13 of the upper annular piston asto its inner surface, but its outer surface slides uponthe wall of the cylinder A, this outer surface of the piston C is provided with a depending. extension C The trunk C also slides or reciprocates within the sleeve A formed integrally with the lower cylinder cover A which is secured to the crank chamber. As shown the two cylinder covers A A closing the lower ends of the two working and pump cylinders A A, Fig. l, are cast in one.

The two crank pins D D move together having the same center line and the crank pin 11) being at 180 degrees to the other two, the two annular pistons B and C reciprocate toward and away from each other. in the left hand cylinder'of the pair, Fig. 1, the pistons are shown at their dead points at the maximum distance apart while in the right hand cylinder of Fig. 1, the two pistons are shown in the dead point position closest together. The space G in this cyl-, inder between the two pistons therefore constitutes the combustion chamber of the engme.

The scavenging air enters the sleeve A depending from the cover A and passes through the ports H formed in the innerwall of the annular piston B and then through the openings or ports in the upper wall of the piston, see Fig. 5. This entry of scavenging air takes place when the piston is at its lower dead point as shown in the right hand cylinder, Fig. 1. When the piston reaches the up r dead point or somewhat before it, as s own in the left hand cylinder, the air is'displaced through the longltudinal passage E to the working side of the piston.- i The mixture or new char e is drawn into the annular passage T, F1 1 and 3, and passes through the ports J when the lower piston C is in the position shown in the right hand cylinder into the annular pump chamber between the piston and the cover plate A*. The'mixture is displaced by the return of the piston C to the position shown in the left hand cylinder, through "the right hand cylinder, Fig. 1, the charge '-.is ignited and the explosion or combustion takes place between the two pistons, At the end of the working stroke, the exhaust ports L are uncovered by the piston C, the exhaust gases pass by means of the annular passage L to the exhaust outlet L see Fig. 4.

Air is also drawn from the central tube through the ports H into the engine, and this in addition to the reciprocating movement of the lower piston into and out of the crank chamber causes a draft of air to be continuously circulated through the central tubular channel.

It will be observed that the depending outer extension sleeve formed integrally with the lower annular piston serves as a closure for the exhaust ports during the induction of the mixture to the lower annular pump.

IVhat I do claim as my invention and desire to secure by Letters Patent. is

1. In an internal combustion engine,the combination of a cylinder, opposed annular pistons working in the cylinder, each of the pistons being provided with an opening extending centrally and longitudinally through the same, and one of the pistons having a trunk extension extending from its central opening and slidably fitting within the opening of the other piston. a stationary sleeve at one end of the cylinder slid ably engaging the said trunk extension, said sleeve opening to the atmosphere at one ..end and communicating at its other end with the trunk extension, means for introducing an explosive charge into the cylinder between the pistons, and 'means for igniting the charge.

2. In an internal combustion engine, the combination of a cylinder, opposed annular pistons working in the cylinder, said pistons being provided with concentric chan nels extending centrally therethrough and with trunk extensions slidably each other, a crank caseat one end of the cylinder in communication with the trunk extensions of both of the said pistons, a stationarv sleeve at; each end of the cylinder tting within and slidably engagingthe trunk extension of one of the pistons, one of said sleeves being open to the atmosphere at one end, means for introducing an explosive charge into the cylinder between the pistons. and means for igniting the charge.

3. In an internal combustion engine, the

combination of a cylinder, opposed annular pistons working in the cylinder, each of the pistons being provided with an opening exengaging charge into the tending longitudinally through the same, v and with a trunk extension slidably fitting within the trunk'extension of the" other piston, fixed sleeves at opposite ends of the cylinder slidably fitting the respective trunk extensions the respective sleeves and trunk extensions forming with the cylinder ump chambers at one side of the pistons, a1r in-' let ports afl'ording communication with one of said pump chambers and to the working space between the pistons, and mixture inlet ports afi'ording communication with the other of said pump chambers and the workmg space between the pistons, the air inlet.

and mixture inlet ports being controlled by the. pistons, charge in the working space between the pistons.

4. In aninternal combustion engine, the

combination of a cylinder, opposed annularand means for igniting the pump chambers and the working space between-the pistons, and mixture inletports affording communication with the other of said pum chambers and the working space between t e pistons, and means for igniting a charge in the working space between the pistons.

' 5. In an internal combustion engine, the combination with a cylinder, opposed annular pistons in the cylinder, one of the pistons being provided with an opening extending centrally and. longitudinally through the same, and with, a trunk. extension, a fixed sleeve at one end of the cylinder, said sleeve opening at one end to the atmosphere and slidably fitting and communicating with the trunk extension, ports in the said piston adapted to be brought into communication with the interior of the fixed sleeve when the piston is in its inder having passages adapted to form a communication between the space at one side of said piston and the working space between the pistons during the return stroke of the piston, means for exhausting gas from the combustion space between the pistons,fmeans for introducing an explosive working space between the pistons, and means for igniting the charge.

6. In an internal combustion engine, the

combination of a. cylinder, opposed annular pistons working in the cylinder, both of the pistons being provided with openi innermost position, said cyl being open to the atmosphere at one end and communicating with the said trunk exten-- sion, ports in one of the pistons adapted to be brought into communication with the interior of the fixed sleeve when the said piston is in its innermost position, the cylinder baring passages adapted to form'a.

communication between the space at one side of the said piston and the space between the pistons during the return stroke of the piston, means for exhausting gas from the space between the pistons, means for introducing an explosive charge between the pistons, and means for igniting a charge between thepistons.

7. In an internal combustion engine, the combination of a cylinder, opposed annular pistons working in the cylinder, and connected respectively to the pistons, both pistons being provided with openings extending centrally and longitudinally through the same and with trimk extensions slidably "fitting one within the other, a crank case at one end of the cylinder in communication with the trunk extension of one of the pistons,"a stationary sleeve at the other end of the cylinder fitting within and slidably engaging the trunk extension of one of the pistons, said sleeve being open to the atmosphere at one end and in counication with the interior of the said tr extension,

intense me for introducing an losirve charge into the cylinder-between the pistons, and,

means for igniting a charge between the pistons.

8. In an internal combustion engine, the combination of a cylinder, opposing pistons working in the cylinder, compression and combustion taking place between the pistons, means at one end of the cylinder for delivering mixture between the pistons, said means including the outer face of one piston and a stationaryfsleeve' exteng within the cylinder from the head at oneend thereof, and

means for delivering compressed air between the pistons, said last mentioned means ineluding the outer face otthev other-piston,

and a stationary sleeve extending intothe cylinder from the head at' the other end-Pot the cylinder, substantially as described.

9. In an internal combustion engine, the

combination of a cylinder, two -"opposing pistons working in the cylinder, compression and combustion taking place between 'the pistons, said pistons baring trunk extensions sliding one within the other, sleeves 

